Buying a 9-volt battery is now the simplest way to upgrade your home to a smart home. The Roost Smart Battery for smoke alarms and carbon monoxide detectors is now available to pre-order for shipment in September this year.

What sets this battery apart is that it has built in Wi-Fi that sends alerts from your standard smoke detector (or similar devices that take a 9-volt battery) to your smartphone via the free app for iOs and Android. Once the battery is installed it connects to the home Wi-Fi and listens for the detector's alarm.

When an alarm sounds, the app sends an alert to the mobile devices connected in your Roost account - which can be your phone, your partner's, or a trusted neighbor's. If the alert is innoucous - burned toast or something similar - then you can snooze the alarm and get back to cooking.

“We have been working hard to design a product that leverages your existing infrastructure – making your existing devices smart through a simple retrofit,” said Roel Peeters, Roost CEO and co-founder in a press release. “With the Roost Smart Battery, we address a real problem and improve the safety of your family and your home in a simple, yet affordable way.”

Each battery is $35, buy two and it's $65, and no subscription or account is required. The batteries wear out and die like regular 9-volts in a few years, but you don't need to buy a whole new battery. Due to its two-piece design, the battery splits in two so you can swap out just the battery section with a $15 replacement. The batteries and replacements are available to purchase through the offical website or on Amazon.